The director of Japan’s damaged Fukushima nuclear power plant is stepping down due to illness, with officials refusing to confirm whether his condition is radiation related.

Masao Yoshida, 56, has been hospitalised for “treatment of illness” and will relinquish his director post at Fukushima Daiichi nuclear power plant in northeast Japan from Thursday.

His sudden departure without a specific medical explanation is likely to prompt speculation surrounding the possible connection between his medical condition and exposure to high radiation levels at the plant.

However, officials at Tokyo Electric Power Co (TEPCO), operators of the plant, declined to comment on whether Mr Yoshida’s illness was connected to radiation exposure.